Currently, there are a number of personal care products that are available to consumers, which are directed toward improving the physical appearance and health of keratinous tissues such as the skin, hair, and nails. The majority of these products are directed to delaying, minimizing or even eliminating skin wrinkling and other histological changes typically associated with the aging of skin or environmental damage to human skin. Numerous compounds have been described in the art as being useful for regulating skin condition, including regulating fine lines, wrinkles, skin texture, sagging and skin discoloration.
Mammalian keratinous tissue, particularly human skin, is subjected to a variety of insults by both extrinsic and intrinsic factors. Such extrinsic factors include ultraviolet radiation, environmental pollution, wind, heat, infrared radiation, low humidity, harsh surfactants, abrasives, etc. Intrinsic factors, on the other hand, include chronological aging and other biochemical changes from within the skin. Whether extrinsic or intrinsic, these factors result in visible signs of skin damage. Typical skin damage includes thinning of the skin, which occurs naturally as one ages. With such thinning, there is a reduction in the cells and blood vessels that supply the skin as well as a flattening of the dermal-epidermal junction that results in weaker mechanical resistance of this junction. See, for example, Oikarinen, “The Aging of Skin: Chronoaging Versus Photoaging,” Photodermatol. Photoimmunol. Photomed., vol. 7, pp. 3-4, 1990. Other damages or changes seen in aging or damaged skin include fine lines, wrinkling, hyperpigmentation, sallowness, sagging, dark under-eye circles, puffy eyes, enlarged pores, diminished rate of turnover, and abnormal desquamation or exfoliation. Additional damage incurred as a result of both external and internal factors includes visible dead skin (i.e., flaking, scaling, dryness, roughness).
Therefore, there is a need for products and methods that seek to remedy these keratinous tissue conditions. A large number of skin care actives are known in the art and used to improve the physical appearance and/or health of the skin. For example, salicylic acid and benzoyl peroxide are used in skin care compositions to treat acne. Retinoids are another example of skin care actives used in skin care compositions to reduce signs of aging skin. Although formulating skin care compositions with such actives provide skin care benefits, there are also challenges in formulating such compositions. For example, retinoid compositions typically have to be prepared under specialized conditions, such as inert atmosphere, and may exhibit less than optimal stability, such as discoloration, at times. Some skin care actives may result in skin irritation, such as stinging, burning and redness.
Based on the foregoing, there is a continuing need to formulate skin care compositions which improve the physical appearance and/or health of the skin, which are for example, aesthetically pleasing, stable and effective at treating the appearance of wrinkles, fine lines, pores, poor skin color (redness, sallowness and other forms of undesirable skin surface texture).
Surprisingly, it has now been found that compositions containing dialkanoyl hydroxyprolines compounds, their salts and derivatives thereof when in combination with hexamidine compounds, its salts and derivatives thereof and/or sugar amine compounds, its salts and derivatives thereof provide benefits in regulating skin condition previously unrecognized in the art of which the inventors are aware. For example, topical application of dipalmitoyl hydroxyproline and hexamidine and/or N-acetyl glucosamine is believed to synergistically regulate (prophylactically and/or therapeutically) visible and or tactile discontinuities in mammalian skin. Additionally surprising is the fact that neutralized salts of dialkanoyl hydroxyprolines can be incorporated into the aqueous phase of a composition, such as a solution or an emulsion resulting in improved stability of these compositions.
For instance, Applicants have found that such compositions may be useful for preventing, retarding, and/or treating dark under-eye circles, puffy eyes, sagging, sallowness as well as spider vessels and/or red blotchiness of skin, promoting skin desquamation, exfoliation, and/or turnover, regulating and/or reducing pore size appearance, preventing/retarding tanning, regulating oily/shiny appearance, preventing, retarding, and/or treating hyperpigmentation (such as post-inflammatory hyperpigmentation, pigment spots such as age spots, and the like) in mammalian skin, preventing, retarding, and/or treating itchiness of mammalian skin, preventing, retarding, and/or treating dryness of skin, preventing, retarding, and/or treating fine lines and wrinkles, preventing, retarding, and/or treating skin atrophy of mammalian skin, softening and/or smoothing lips, hair and nails of a mammal, and preventing, retarding, and/or treating the appearance of cellulite in mammalian skin.